Rapid Energized Dispersive Solid Phase Extraction (SPE) for Analytical Analysis

Abstract

An energized dispersive extraction method for sample preparation for analysis is disclosed. The method includes the steps of placing an extraction solvent, sorbent particles, and a sample matrix containing an analyte in a heat conductive sample cup; positioning the sample cup in a pressure-resistant reaction chamber; dispersing the solvent and the sample matrix in the sample cup in the reaction chamber; heating the sample matrix and the solvent in the sample cup in the reaction chamber to a temperature that generates an above-atmospheric pressure; draining the solvent extract from the sample cup at atmospheric pressure; and collecting the solvent extract for analysis.

1 . A dispersive extraction based sample preparation method comprising the steps of:
 placing an extraction sample and sorbent particles into a heat conductive sample cup surrounded by a reaction chamber with the heat conductive sample cup having one opened filtered end;   adding extraction solvent to both the inside of the sample cup and to the reaction chamber outside of the sample cup; and   heating the solvent in the reaction chamber outside of the sample cup to in turn heat the sample cup, heat the solvent inside the sample cup, and heat the extraction sample and the sorbent particles inside the sample cup.   
     
     
         2 . An extraction method according to  claim 1  wherein the step of heating the solvent outside of the sample cup comprises heating the reaction chamber. 
     
     
         3 . An extraction method according to  claim 1  wherein:
 the sample cup has a mouth opposite from its open filtered end; and 
 the extraction method further comprises: 
 sealing the sample cup between a sealing cover at the vessel mouth and an outlet valve in fluid communication with the open filtered end of the sample cup so that the heating step increases the vapor pressure of the extraction solvent above the solvent's vapor pressure at standard temperature and pressure. 
 
     
     
         4 . An extraction method according to  claim 1  further comprising pre-pressurizing the reaction chamber to about 25 psi between the steps of adding the solvent to the sample cup and of heating the solvent in the reaction chamber. 
     
     
         5 . An extraction method according to  claim 3  wherein the step of adding extraction solvent into the sample cup is carried out from positions selected from the group consisting of the top of the sample cup, the bottom of the sample cup, and both the top and bottom of the sample cup. 
     
     
         6 . An extraction method according to  claim 3  and further comprising:
 releasing the outlet valve on the sample cup so that the vapor pressure in the sample cup drives the extractions solvent out of the sample cup through the open filtered end and through the outlet valve; and 
 collecting the extraction solvent for analysis. 
 
     
     
         7 . An extraction method according to  claim 6  further comprising driving the solvent into a chiller for a time sufficient to reduce the temperature of the extraction solvent to below the solvent's boiling point at ambient pressure in the chiller. 
     
     
         8 . An extraction method according to  claim 7  in which the chiller is a cooling coil in liquid communication with the open filtered end of said sample cup and the cooling coil has a length sufficient to reduce the temperature of common extraction solvents from between about 50° C. and 150° C. to between about 25° C. and 40° C. as the solvent travels the length of the cooling coil. 
     
     
         9 . A dispersive solid phase extraction based sample preparation method comprising:
 heating a sample cup, a sample matrix, sorbent particles and an extraction solvent in a pressure-resistant reaction chamber until the temperature generates an above-atmospheric pressure that together with the increased temperature drives the analyte substantially from the sample matrix into the extraction solvent;   while dispersing the sample matrix, the sorbent particles and the extraction solvent in the sample cup; and   releasing the solvent extract from the sample cup into a cooling tube at atmospheric pressure in which the cooling tube has a length sufficient to substantially cool the solvent extract to ambient or near-ambient temperature; and   collecting the cooled solvent extract for analysis.   
     
     
         10 . A dispersive extraction based sample preparation method according to  claim 9  wherein the step of heating the sample cup in the chamber comprises heating a thermally responsive chamber to in turn heat the sample cup, the extraction solvent, the sorbent particles and the sample matrix. 
     
     
         11 . A dispersive extraction based sample preparation method according to  claim 9  wherein the extraction solvent is selected from the group consisting of water, weak acids, weak bases, ethyl acetate, methyl tertiary-butyl ether (“MTBE”), methylene chloride, hexane, acetone, 2-propanol, cyclohexane, acetonitrile, methanol and mixtures thereof. 
     
     
         12 . A dispersive extraction based sample preparation method according to  claim 9  further comprising an ultrasonic agitation step during the pressurized heating step. 
     
     
         13 . A dispersive extraction based sample preparation method according to  claim 9  further comprising adding buffering salts to the sample cup prior to the step of heating the sample cup. 
     
     
         14 . A dispersive extraction based sample preparation method according to  claim 9  further comprising analyzing the cooled solvent extract using a method selected from the group consisting of mass spectrometry, gas chromatography mass spectroscopy, ultraviolet spectroscopy, infrared spectroscopy, nuclear magnetic resonance spectroscopy, and successive or concurrent uses of each. 
     
     
         15 . A dispersive extraction based sample preparation method according to  claim 9  wherein the step of placing the sorbent particles into a sample cup with an extraction solvent and a sample matrix comprises placing particles selected from the group consisting of silica, silica particles with functional groups bonded to their surface alumina, alumina particles with functional groups bonded to their surface, alumina pre-treated to create acidic, basic, or pH neutral slurries in water, and combinations thereof. 
     
     
         16 . A dispersive extraction method for preparing analytes for molecular analysis, the method comprising:
 adding a liquid sample matrix to a plurality of sorbent particles in a sample cup;   thereafter dispersing, heating, and pressurizing the solvent-carrying sorbent particles in the sample cup to extract the analyte from the heated liquid sample matrix and into the solvent carried by the sorbent particles;   thereafter draining the pressurized heated liquid matrix at atmospheric pressure from the sample cup;   thereafter adding a release solvent to the plurality of sorbent particles carrying the extraction solvent and the analyte;   thereafter dispersing, heating, and pressurizing the release solvent and the sorbent particles to release the analyte into the release solvent;   thereafter draining the pressurized heated release solvent at atmospheric pressure.   
     
     
         17 . A dispersive extraction method according to  claim 16  wherein:
 the draining step is carried out until the drained release solvent approaches or reaches ambient temperature; and 
 thereafter collecting the cooled release solvent for analysis. 
 
     
     
         18 . A dispersive extraction method according to  claim 16  wherein the sorbent particles are formed of a physically durable water-insoluble polymer resin, in a mesh size retained by the porous flexible sleeve, with a broad distribution of pore sizes and that remains stable at the temperatures and pressures generated in the extraction steps. 
     
     
         19 . A dispersive extraction method according to  claim 16  wherein the sorbent particles are formed of a resin selected from the group consisting of hydrophobic crosslinked polystyrene copolymer resin; polymers of styrene crosslinked with divinylbenzene; and polymerized methacrylic acid ester. 
     
     
         20 . A dispersive extraction method according to  claim 16  wherein the dispersing step precedes the heating and pressurizing steps. 
     
     
         21 . A dispersive extraction method according to  claim 16  wherein the dispersing step comprises feeding a gas that is inert to the solvent, the particles and the analyte into the sample cup. 
     
     
         22 . A dispersive extraction method according to  claim 16  wherein the step of draining the pressurized heated release solvent at atmospheric pressure comprises draining the heated release solvent into a coil with a length sufficient to cool the drained release solvent to approach or reach ambient temperature in the coil. 
     
     
         23 . A dispersive extraction method according to  claim 16  wherein the extraction solvent in the particles is selected from the group consisting of water, weak acids, weak bases, ethyl acetate, methyl tertiary-butyl ether (“MTBE”), methylene chloride, hexane, acetone, 2-propanol, cyclohexane, acetonitrile, methanol and mixtures thereof. 
     
     
         24 . A dispersive extraction method according to  claim 16  comprising heating the sample matrix, the sorbent particles and the extraction solvent to a temperature of between about 50° C. and 150° C. and generating a resulting pressure of between about 50 and 250 psi. 
     
     
         25 . A dispersive extraction method for preparing analytes for molecular analysis, the method comprising:
 collecting a cooled extraction solvent extract for analysis that has been drained from a sample cup after the extraction solvent, the sorbent particles and a sample matrix containing an analyte have been placed into the sample cup, and dispersed, heated, and pressurized, and the solvent extract has thereafter been cooled.   
     
     
         26 . A heated pressurized dispersed mixture of an extraction solvent, sorbent particles, and a sample matrix containing an analyte in a sample cup.